Agriculture Reference
In-Depth Information
with cultivars released by the national program. INIA releases all
cultivars under plant protection regulations, and the rice breeding
program licenses cultivars to a consortium integrated by seed produc-
tion departments of the rice industry(GMA)andfarmers(ACA),which
ensures ample distribution of available cultivars with high-quality
seed (95% of the area is sown with certi
ed seed).
Blanco et al. (2003) reviewed the procedures followed by INIA
'
srice
breeding program. In recent years, in coordination with INIA
sbio-
technology unit, biotechnological tools were incorporated into the
program, and a regional rice biotechnology laboratory was also estab-
lished at EEE-INIA Treinta y Tres. Marker-assisted selection has been
implemented, with a focus on identifying and introgressing blast
resistance genes (Rosas et al. 2012), as well as allele discovery for
traits such as cold tolerance at the vegetative stage (Bonnecarrère
2013). Currently, a project on association mapping is being conducted
with the objective of identifying molecular markers associated with
grain yield, resistance to stem and sheath diseases, and grain quality.
Final evaluation processes incorporate testing of cold tolerance under
controlled conditions, evaluating promising cultivars in regional strip
tests, and validating them in commercial
'
fields before release, in
agreement with the private sector. In the 2012
-
2013 rice-growing
season, selection was performed on 33,400 F
3
-F
6
lines and 1,833
breeding lines were included in yield tests.
5. Cultivar Development
Tropical Japonica.
The cultivars released in the 1980s were El Paso 48,
El Paso 94, and El Paso 227. Among these, the
rst one was under
cultivation for 8 years, reaching 16% of the crop area. These cultivars
were followed by INIA Yerbal (1991), INIA Tacuarí (1992), INIA Car-
aguatá (1995), INIA Zapata (1999), and Parao (2012). INIA Tacuarí has
been the most successful of them, being cultivated for 18 years and
reaching a maximum of 37%of the crop area (Fig. 5.4). This short-season
variety has good cold tolerance during the reproductive phase, superior
grain quality, and its grain yield was 20% higher than that of Bluebelle.
However, INIA Tacuarí is susceptible to sheath spot and aggregate
sheath spot, moderately susceptible to blast, and its grain weight is
only 21.5mg. INIA Tacuarí provided
flexibility for sowing dates and
helped to increase and stabilize grain yield, being complementary with
El Paso 144, which is a long-season and cold-susceptible variety (Blanco
et al. 2003). New variety Parao, which was grown in 1% of the area in
2012
-
2013, has 8% higher grain yield than INIA Tacuarí, larger grains
